Subtracting DateTime Value

[kenomote]

Hey guys i need some help on how to Subtract the Dates i used a readline for sotring the number of fines per day on a txt file....now i wanted to know how do you subtrack the date the book borrowed and the date it was returned
then multiplying the that value to the value of the fines that i stored on a txt file...

in short getting the value of Subtracted Dates and multiplying it to the value on the txt file.

Heres the code for reading the txt file:
also below is where i formated the dates into "yyyy-MM-dd"

'Dim b As String
        'Dim re As String
        'Dim days As String
        'Dim months As String
        'Dim years As String

        'Dim Sett As String = "C:\Settings.txt"

        'If System.IO.File.Exists(Sett) = True Then
        '    Dim objWriter As New System.IO.StreamReader(Sett)
        '    b = objWriter.ReadLine
        '    objWriter.Close()
        'End If

        'Dim strArr() As String
        'Dim count As Integer

        'strArr = b.Split(",")
        'For count = 1 To strArr.Length - 1



        '    If count = 1 Then

        '        re = DateTimePicker1.Value.AddDays(strArr(count))

        'Dim strArrs() As String
        'Dim counts As Integer

        'strArrs = re.Split("/")
        'For counts = 1 To strArrs.Length - 1

        '    If counts = 1 Then
        '        days = strArrs(counts)
        '    ElseIf counts = 1 Then
        '        months = strArrs(counts)
        '    ElseIf counts = 2 Then
        '        years = strArrs(counts)
        '    End If
        'Next


        'lblDTBR.Text = years & "-" & days & "-" & months


        '    End If


        'Next